Conversion of hydrocarbon oils



July 2, 1935. J. B. HEID CONVERSION OF HYDROCARBON OILS Filed Dec. 11,1931 FRACTIONATOR FURNACE 7,

INVENTOR JACOB BENJAMIN HEID BY 0%W ATT Patented July 2, 1935 CONVERSIONOF HYDROCARBON OILS Jacob Benjamin Heid, Chicago, 111., assignor toUniversal Oil Products Company, Chicago, 111.,

a. corporation of South Dakota Application December 11 ,-1931, SerialNo; 580,352

g 2 Claims. (01. 196-49) This invention relates to the conversion ofhydrocarbon oils and more particularly refers to the conversion ofrelatively heavy oils or oils of inferior quality for the production ofsubstan- 5 tial yields of desirable light products such as motor fuel ofhigh antiknock value.

The primary principles of the present invention-comprise subjecting ahydrocarbon oil to relatively mild conversion conditions and thencesubjecting the total liquid and vapcrous products of such' relativelymild conversion to further treatment under more severe" conversionconditions. I

'The relatively mild conversion conditions to which the charging stocksupplied-to the system is first'subiected are preferably of a naturesuch as will effect the production of from'lo to so percent, orthereabouts, based on the charging stock, of materials of substantially'rnotor fuel boiling 90 range. The percentage of such material producedby the initial conversion will, of course, vary with different chargingstocks and different conversion conditions, but the extent of conversionof the charging stock in this initial stage of the process is heldwithin the limits which preclude any substantial formation of coke orcarbonaceous material or any other heavy residual products which wouldform extensive quantities of coke or carbonaceous materialin the heatingelement of 30 the succeeding conversion range. The features of theinvention thus permit the production, from a wide variety of chargingstocks, under initial conversion conditions in the system,jof a selectcharging stock suitable for conversion in, the succeeding conversionstages of the system to produce substantial yields of desirable lightproducts such as motor fuel of high antiknock value;

It should be noted that this method diifers from other cracking systemswherein select charging stocks are produced for further conversion in atleast two important respects; namely, by the method of the presentinvention the raw'oil charging stock is subjected in the primary stagesof the system to conversion rather than to distillation withoutconversion, and furthermore all of the products resulting from saidinitial conversion are collectively subjectedtofurther con versionwithout'removal of any of their components.

A more specific embodiment of the present invention may comprisesubjecting the hydrocarbon oil to relatively mild conversion conditionsin a heating element, introducing the heated materials into anenlargedreaction chamber where conversion, particularly of the vapors,may continue and wherefrom liquid conversion products a may be withdrawnwithout extensive further conversion in this zone, maintaining both theheating element and the reaction chamber under substantialsuperatmospheric pressure, simultaneously withdrawing both liquid andvaporous'prodnote from said reaction chamber and subjecting them tofurther conversion in a separate heating element preferably under moresevere conversion conditions than those employed in the first mentionedheating element, introducing heated materials from said separate heatingelement into a separate enlarged reaction chamber wherein continuedconversion, particularly of the vapors, is effected, maintaining saidseparate heating element and said separate reaction chamber atsubstantial superatrnospheric pressures, introducing both liquid andvaporous products from said separate reaction chamber to a reducedpressure vaporizing chamber where further vaporization of the residualliquid and its separation from the vapors is effected, subjectingvaporsfrom' said vaporizing zone to fractionation whereby theirrelatively heavy component s are condensed, returning said relativelyheavy components either to said separate heating element for furtherconversion or to said first mentioned reaction chamber, or in part toboth, subjecting vapors and gas from the fractionator tocondensation-and cooling, and collecting the resulting distillate andgas, l v

The attached diagrammatic drawing illustrates one specific form ofapparatus embodying the principles and features of the presentinvention;raw oil charging stochfor the system may be supplied through line i andvalve '2 into pump 3, from which'it is fed through line 4 and valve 5 toheating element 6, to be subjected therein to relatively mild conversionconditions by means of heat supplied from a furnace l of any suitableform. The heated oil is discharged from heating element 6 through line 3and valve 9 into reaction chamber iii, which, like heating element 6, ispreferably maintained at substantial superatmospheric pressure. Bothliquid and vaporous products are Withdrawn from chamber I0 through lineH and valve l2 to pump l3, by means of which they are fed through lineM, valve l5 and line it to be subjected to further conversion in heatingelement 11. I

Heating element ll is located in a furnace l8 of any suitable formcapable of supplying the required heat to the oil undergoing conversionand'heated materials are discharged from heat-' ing element Il'throughline l9 and'valve 20 to reaction chamber 2L- Chamber 2! and heating.

element ll are both preferably maintained a substantialsuperatmospheric, pressure: Both liquid and vaporous products'arewithdrawn from chamber 2| through line .22 and Valve 23 and areintroduced, into vaporizing chamber 24, which is preferably maintainedat a substantially reduced pressure relative to that employed in chamber2|. Further vaporization and cooling of the residual oil from chamber 2|and its separation from the vapors is effected in chamber 24. Residualliquid remaining unvaporized in chamber 24 may be withdrawn through line25 and valve 26 to cooling and storage or to any desired furthertreatment. Vapors from chamber 24 pass through line 21 and valve 28 tofractionation in fractionator 29.

The relatively heavy components of the vapors which have not beensufiiciently converted are condensed in fractionator 29, collecting inthe lower portion of this zone to be withdrawn therefrom through line 30and valve 3| to pump 32. Pump 32 supplies the reflux condensate fromfractionator 29 either through line 16 and valve 33 direct to heatingelement IT or, if desired, all or a portion of said reflux condensatemay be diverted from line [6 through line 34 and valve 35 into reactionchamber Ill, commingling there in with the conversion products in thiszone and passing therewith through line H, valve l2, pump l3, line I4,valve l5 and line I6 to further conversion in heating element I'I. Whenall or a portion of the reflux condensate from fractionator 29 issupplied, as described, to chamber In it may serve as a means ofdiluting and cooling the other conversion products withdrawn fromchamber II], but in any case is eventually subjected to furtherconversion in heating element l1.

Vapors from fractionator 29, comprising the desired distillate productsof the system and uncondensable gas, pass through line 36 and valve 31to be subjected to condensation and cooling in condenser 38, distillateand uncondensable gas from which pass through line 39 and valve 40 to becollected in receiver 4|. Uncondensable gas may be released from thereceiver through line 42 and valve 43. Distillate may be withdrawn fromthis zone through line 44 and valve 45. If desired, a portion of thedistillate from receiver 4| may be recirculated, by well known means notillustrated in the drawing, to the upper portion of fractionator 29 toassist fractionation of the vapors in this zone and to maintain thedesired vapor outlet temperature.

Pressures employed within the system may range from atmospheric tosuperatmospheric pressures as high as 2000 lbs. or more per square inch.Conversion temperatures employed may range from 750 to 1200 F., more orless. Preferably the primary conversion stage of the system employsrelatively mild conversion conditions with temperatures at the outletfrom the heating element ranging, for example, from 750 to 850 F., andpressures in both'the heating element and the reaction chamber, whichmay range from 100 to 500 lbs., or more, per square inch and which maybe either substantially equalized between these two zones or may besomewhat reduced in the reaction chamber. In the secondary conversionstage of the system the preferred range of temperature in the heatingelement is from 850 to 950 F., or thereabouts, with pressures rangingfrom 100 to 500 lbs. or thereabouts, per square inch in both the heatingelement and reaction chamber. Preferably the vaporizing chamber and thesucceeding fractionating, condensing and collecting portions of thesystem utilize substantially reduced pressures of the order ofsubstantially atmospheric to 100 lbs. or thereabouts per square inch.

As a specific example of the operation of the process of the presentinvention a 36 A. P. I. gravity Pennsylvania gas oil is the raw oilcharging stock to be treated. It is subjected in the primary heatingelement of the system to a temperature of approximately 820 F. Asuperatmospheric pressure of approximately 250 lbs. per square inch isemployed in both the heating element and reaction chamber of thisportion of the system. A portion of the reflux condensate from thefractionator of the system is introduced into the reaction chamber ofthe primary conversion stage, the remainder being fed together with thetotal products withdrawn from said reaction chamber to the heatingelement of the secondary conversion stage. A temperature ofapproximately 910 F. is employed in the secondary heating element and asubstantially equalized pressure of approximately 350 lbs. per squareinch is employed in this heating element and the succeeding reactionchamber. duced pressure of approximately 35 lbs. per square inch isemployed in the vaporizing, fractionating, condensing and collectingportions of the system. This operation may result in the production ofapproximately '72 percent of motor fuel having an antiknock valueapproximately equivalent to a blend of 80 percent iso-octane and 20percent normal heptane. In addition, about 16 percent of residual oil isproduced, the remaining products of the system being principallyuncondensable gas and a relatively small amount of carbonaceousmaterial.

I claim as my invention:

1. A process for producing high antiknock motor fuel from heavyhydrocarbon oils com prising initially heating the oil to acomparatively mild cracking temperature in a heating coil, thencedelivering the same to the upper end of a vertically elongated reactionchamber wherein substantial vaporization occurs, withdrawing both liquidoil and vapors from the bottom of said vertically elongated chamber,effecting the removal of the liquid at such a rate that no accumulationof a liquid body in the reaction chamber occurs, passing the liquid andvapors withdrawn from the elongated reaction chamber together withreflux condensate formed as hereinafter set forth through a secondheating coil where the conditions are such as to further crack theliquid oil and vapors, increasing the antiknock character of thegasoline components thereof and cracking the reflux condensate,introducing the heated constituents from said second coil to a secondvertically elongated reaction chamber and withdrawing all products fromthe bottom thereof without permitting accumulation of any appreciablebody of liquid in said secondary reaction chamber and efiecting furtherdistillation of the products under reduced pressure, separating thevapors from residue and dephlegmating the same to condense heavierfractions thereof, adding such condensed fractions to said liquid andvapors as said reflux condensate, and finally condensing thedephlegmated vapors.

2. The process as defined in claim 1 further characterized in that saidreflux condensate is added to said liquid and vapors by being introducedto the first-mentioned vertically elongated chamber.

JACOB BENJAMIN HEID.

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